The present invention relates to a method of manufacturing a thin film head, more precisely relates to a method of manufacturing a thin film head, which includes a pad capable of preventing the thin film head from sticking onto a recording medium.
In a contact-start-stop (CSS) type magnetic disk drive unit, magnetic heads contact surfaces of magnetic disks while rotation of the disks are stopped; the magnetic heads are floated above the surfaces of the disks by air streams, which are caused by rotation of the disks. Thus, floating patterns are formed in a disk-side face, which faces the surface of the disk, of each magnetic head. Further, pads, which is capable of reducing contact resistance between the disk and the head, are formed in the disk-side face.
The disk-side face of the conventional magnetic head is shown in FIG. 6. The head 10 has the floating patterns 12a, 12b and 12c, shallow groove sections 14a, 14b and 14c and a deep groove section 16. The shallow groove sections 14a, 14b and 14c and the deep groove section 16 act to generate negative pressure when the magnetic head 10 is floated, so that flatting level of the magnetic head 10 can be limited in a prescribed range. In the disk-side face, the floating patterns 12a, 12b and 12c are projected the most other than pads 18a, 18b, 18c and 18d; the floating patterns 12a, 12b and 12c are projected more than the shallow groove sections 14a, 14b and 14c; the deep groove section 16 is deeper than the shallow groove sections 14a, 14b and 14c. The pads 18a, 18b, 18c and 18d are provided in the shallow groove sections 14a, 14b and 14c, and their end faces are projected from surfaces of the floating patterns 12a, 12b and 12c. FIG. 7 shows a state in which the magnetic head 10 is floating above a surface of a rotating disk 20. The magnetic head 10 is held by a suspension 22.
Each time the rotation of the disk is stopped, the pads contact the surface of the magnetic disk. Therefore, the pads must have enough durability because the pads contact the disk many times. To have enough durability, the contact resistance between the pads and the disk must be reduced, and the sticking of the head to the disk and the sticking of dust to the surface of the head must be prevented so as to reduce the contact resistance less than a prescribed value.
A conventional method of forming the pads is shown in FIGS. 5A-5D. Note that, FIGS. 5A-5D are sectional views taken along a line Axe2x80x94A in FIG. 6.
In FIG. 5A, an adhesion layer 32, a protection layer 34, a stopper layer 36 and a pad layer 38 are piled, in this order, on a surface of a substrate 30 of a head slider, which has been finished by lapping machine. The adhesion layer 32 and the stopper layer 36 are silicon film layers; the protection layer 34 and the pad layer 38 are DLC (Diamond Like Carbon) film layers.
In FIG. 5B, the pad layer 38 has been etched, then the stopper layer 36 have been etched so as to form a pad 18. In the etching step, the surface of the pad layer 38 is coated with resist 40, and a resist pattern, which covers over a portion at which the pad 18 is formed, is formed by exposing and developing processes. Then etching is executed.
The pad layer 38 is dry-etched in oxygen gas, then the portion covered with the resist 40 is left and the pad 18 is formed. The stopper layer 36 is selectively etched with CF4 gas. By the etching step, the protection layer 34 other than the portion corresponding to the pad 18 is exposed.
In FIG. 5C, a floating pattern 12 and a shallow groove section 14 are formed. Resist 42 covers over the floating pattern 12 and the pad 18. The protection layer 34, which is the DLC layer, is dry-etched so as to form the floating pattern 12, then the adhesive layer 32 and the substrate 30 are etched by ion milling so as to form the shallow groove section 14. In this step, the surface of the substrate 30 is wholly etched.
In FIG. 5D, a deep groove section 16 is formed in the substrate 30. To etch a portion corresponding the deep groove section 16, the pad 18, the floating pattern 12 and the shallow groove section 14, other than the portion corresponding to the deep groove section 16, are covered with resist 44. The surface of the substrate 30 is etched, by ion milling or dry-etching, so as to form the deep groove section 16 in the surface of the substrate 30.
In the conventional method in which the pad 18 is formed in the disk-side face of the head 10, the stopper layer 36 is formed on the protection layer 34 so as not to etch the lower protection layer 34 when the pad layer 38 is etched.
Silicon invades into the protection layer 34 and a mixing layer is formed in the protection layer 34 when the silicon stopper layer 36 is formed on the protection layer 34. Forming the mixing layer is unavoidable. The silicon in the protection layer 34 cannot be removed by etching and removing the stopper layer 36, and it makes water-repellent property of the protection layer 34 lower. On the other hand, if the stopper layer 36 is etched for a long time so as to perfectly remove the silicon in the protection layer 34, the protection layer 34 is damaged and has a porous structure. In this case, the protection layer 34 is apt to be corroded, and its corrosion-resisting property must be lowered.
The present invention was invented to solve the problems of the conventional method of forming the pads in the magnetic head.
An object of the present invention is to provide a method of manufacturing a thin film head, which includes a protection layer having enough corrosion-resisting property and water-repellent property, which is capable of keeping the magnetic head clean even if temperature and humidity are high, and which has enough durability and reliability.
To achieve the object, the method of manufacturing the thin film head, in which a pad, which contacts a disk, and a floating pattern are formed in a disk-side face, comprises the steps of: forming a adhesion layer on the disk-side face of a substrate, which is a main body of the thin film head; forming a protection layer on the adhesion layer; coating the protection layer with resist; patterning the resist so as to form a pad hole at a prescribed position, at which the pad is formed; forming a pad film on resist-coated faces including an inner face of the pad hole; and lifting off the resist so as to form the pad.
In the method, a diameter of the pad hole in the resist may be greater than that of the pad, and the pad, which has a prescribed shape, may be formed by etching the pad film after the resist is lifted off. By making the diameter of the pad hole greater than that of the pad, the pad can be precisely formed with predetermined thickness and shape.
In the method, a preferable relationship between a thickness xe2x80x9ctxe2x80x9d of the resist and a radius difference xe2x80x9cLxe2x80x9d, which is a difference between a radius of the pad hole and that of the pad, is Lxe2x89xa70.5t.
In the method, the pad film and the protection layer may be coated with another resist after the resist is lifted off, the another resist may be patterned so as to coat prescribed positions, at which the pad and the floating pattern are respectively formed, with the another resist, and the pad film, the protection layer and a surface of the substrate may be etched so as to form the pad and the floating pattern.
In the method, a water-repellent treatment may be executed on the disk-side face after forming the pad and the floating pattern. With this structure, the disk-side face can have higher water-repellent property, so that the disk-side face can be kept clean and the reliability of the head can be improved.
In the method, a base film may be formed as a base layer of the pad film so as to improve abrasion-resisting property of the pad. Hard film, e.g., silicon film, SiC film, is properly employed as the base film.
In the method of the present invention, the corrosion-resisting property of the floating pattern, etc., which are formed in the disk-side face of the head, and the water-repellent property of the surface of the head can be improved, so that the thin film head having high durability and reliability can be manufactured.